Wilting Carnations

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Carnations (Dianthus caryophyllus), also known as clove pinks, saturate their surroundings with spicy, sweet fragrance and a carnival of color. Carnations grow as compact garden-border varieties with stems of multiple, white, yellow, pink or red 2-inch blossoms or as florist's carnations with 3-inch, single flowers in every shade but blue. Reliably hardy in U.S. Department of Agriculture plant hardiness zones 5 through 9, these typically disease-resistant plants occasionally wilt from fungal or bacterial infection.

Fusarium Stem Rot

Carnations with wilted tops and rotting stems and roots suffer from Fusarium (Fusarium avenacearum, F. graminearum, F. culmorum) stem rot. These pathogens may produce clumps of pink spores around the bases of the plants. Their water-borne spores survive in soil or previously infected plant debris and spread to new plants in warm, rainy weather. Avoiding high-nitrogen fertilizers that stimulate susceptible new growth and promptly disposing of infected plants manage the disease.

Fusarium Wilt

Fusarium wilt fungus (Fusarium oxysporum f. sp. dianthi) yellows, wilts and kills a carnation's foliage, often on one side of the plant. Like Fusarium stem rot, it may cover diseased plant tissue with cushion-like pink spores. They spread during wet weather at soil temperatures above 75 degrees Fahrenheit. Planting your carnations in well-drained soil, watering them only as needed and avoiding high-nitrogen fertilizers discourage Fusarium wilt.

Phialophora

Cool, wet weather raises carnations' small risk of Phialophora wilt (Phialophora cinerescens) disease. Infected foliage and stems fades to gray or straw-yellow as the plants gradually wilt. In its advanced stages, the fungus browns the carnation's vascular moisture- and nutrient-conducting system without rotting their tissues. The entire plant may uproot after dying. Water-transported Phialophora spreads from infected soil and plants. Remove diseased carnations as the first symptoms surface.

Rhizoctonia Stem Rot

Rhizoctonia stem-rot (Rhizoctonia solani) fungus attacks carnations at the soil line. Its initial symptom is basal-stem browning or blackening; the discoloration ascends the stem as the disease advances. The carnations yellow, wilt and die as the stems stop transporting water and nutrients. During warm weather, Rhizoctonia targets stressed plants growing in wet soils. Giving your carnations a well-drained location, watering and fertilizing them as needed to maintain their vigor and destroying infected plants contain the disease.

Bacterial Wilt

Wounded carnation stems and branches invite bacterial wilt (Pseudomonas caryophylli) invasion. Wilt-infected stems become brown or yellow and crack around their bases. The plants' leaves and flowers develop small wet spots that blacken as they spread. During rainy weather, brown bacterial colonies may ooze from diseased tissue. Warm, rainy conditions encourage bacterial wilt. Planting your carnations in well-drained soil, spacing for adequate air circulation between plants and watering from beneath to avoid wetting their foliage all protect them against this disease. Like fungal-infected plants, carnations with bacterial wilt require immediate removal and disposal.

About the Author

Passionate for travel and the well-written word, Judy Wolfe is a professional writer with a Bachelor of Arts in English literature from Cal Poly Pomona and a certificate in advanced floral design. Her thousands of published articles cover topics from travel and gardening to pet care and technology.